Those steps included a reported Friday meeting with a major labor official, Harold Schaitberger, president of the International Association of Fire Fighters.

CNN's Jim Acosta reported that Biden "talked about campaign strategy with Schaitberger and indicated a final decision on whether he would run for president is imminent."

"The source described the call as one of many the vice president is making to potential backers of a Biden candidacy," Acosta added.

Additionally, billionaire grocery-store magnate John Catsimatidis said during his Sunday morning radio show, "The Cats Roundtable," that he had recently spoken with Biden. And Biden apparently seemed ready to launch a campaign for the White House.

"I was with Vice President Joe Biden last night," Catsimatidis said. "He was in New York. I spent about five minutes with him. I don't know — I think he may run. You never know."

If Biden does enter the race, he will scramble what has thus far been a virtual one-on-one primary race between former Secretary of State Hillary Clinton and Sen. Bernie Sanders (I-Vermont).

Polls suggest Clinton will remain the clear front-runner for the Democratic nomination. But Biden could offer establishment Democrats a more mainstream alternative than Sanders, who self-identifies as a democratic socialist. In particular, some Democrats are worried about whether Clinton's email controversies could damage her general-election chances.

But a Biden candidacy seems anything but a sure bet.

The Wall Street Journal reported over the weekend that though "signs point to him running," Biden "could still pull back, however, if he concludes he is too shaken by his son's death to mount a campaign."